Small-time con man Konrad Kujau needs to make money. To do so, he decides to forge Hitler's diaries, one of which ends up in the hands of Stern magazine reporter Gerd Heidemann who is determined to get his hands on more.
Looking for evidence of the diaries' origins, Heidemann travels to East Germany, where he meets up with secret police. Meanwhile, Elisabeth finds herself struggling to balance work and a new romance.
Kujau's con goes deeper when Stern demands an expert opinion on the diaries. Meanwhile, Heidemann travels to Boston to buy the publication rights to the diaries from Hitler's cousin, and a young, mysterious man blackmails Elisabeth.
Heidemann accidentally leaves a folder with pages from the diaries with a US media mogul, risking Stern's world exclusive. On the forger's trail, Elisabeth learns her father still isn't telling her the whole truth.
The Stern special edition must be rushed to print, but the editors don't know about the diaries; when Elisabeth speaks openly about her belief that they are fake, she finds herself out of a job; Kujau puts Heidemann under pressure.
The West German criminal police conduct a scientific examination and issue the final word on the authenticity of the diaries; Kujau, after a brief escape attempt, returns to face punishment and fame.